3 8 Laboratory Guide in Zoology 



XIII. — Above the pyloric sac is the intestine, but on ac- 

 count of its small size it was probably torn away with 

 the body wall. Make out a similar connection between 

 the pyloric sac and the digestive glands in the other 

 rays. 



XIV. — Upon the surface now exposed, muscles were ar- 

 ranged which lifted the rays and moved them from 

 side to side. They were probably cut away when the 

 integument was removed. Try to find parts of them 

 extending from the centre of the body along the me- 

 dian line of each ray. 



XV. — Turn back both hepatic coeca and observe the 

 stomach carefully. Notice its large, blunt projection, 

 the cardiac pouch, extending into each ray a short dis- 

 tance. Push this carefully ^side, and see the narrower 

 part below, corresponding to an oesophagus or gullet, 

 into which the mouth opens. 



XVI. — On each side of the ray, at its very base, and 

 attached to the walls separating that ray from the adja- 

 cent rays, find two small white or orange colored lobed 

 bodies, shaped something like a single digestive gland : 

 these are the reproductive bodies. At the place of 

 attachment, there is an opening in the body wall for the 

 passage of the contents. See if there are two, similarly 

 placed, in each of the other rays. These organs are 

 either ovaries or testes ; that is, the sexes are separate. 

 The eggs are fertilized, and the development of the 

 young starfish takes place outside of the body. 



XVII. — You will notice a very interesting arrangement of 

 the parts now exposed on the floor of the ray. Keep 

 the specimen constantly under water. See four rows 

 of colorless, inflated, closed tubes : they resemble in 

 arrangement the tube feet just below them on the 



